Merge branch 'w31_MDL-40891_m24_mkdirrace' of https://github.com/skodak/moodle into MOODLE_24_STABLE

cache/stores/file/lib.php

@@ -266,7 +266,7 @@ class cachestore_file extends cache_store implements cache_is_key_aware, cache_i
         $this->definition = $definition;
         $hash = preg_replace('#[^a-zA-Z0-9]+#', '_', $this->definition->get_id());
         $this->path = $this->filestorepath.'/'.$hash;
-        make_writable_directory($this->path);
+        make_writable_directory($this->path, false);
         if ($this->prescan && $definition->get_mode() !== self::MODE_REQUEST) {
             $this->prescan = false;
         }
@@ -320,7 +320,7 @@ class cachestore_file extends cache_store implements cache_is_key_aware, cache_i
             $dir = $this->path . '/' . $subdir;
             if ($create) {
                 // Create the directory. This function does it recursivily!
-                make_writable_directory($dir);
+                make_writable_directory($dir, false);
             }
             return $dir . '/' . $key . '.cache';
         }

lib/setuplib.php

@@ -1236,10 +1236,15 @@ function make_writable_directory($dir, $exceptiononerror = true) {
 
     if (!file_exists($dir)) {
         if (!mkdir($dir, $CFG->directorypermissions, true)) {
-            if ($exceptiononerror) {
-                throw new invalid_dataroot_permissions($dir.' can not be created, check permissions.');
-            } else {
-                return false;
+            clearstatcache();
+            // There might be a race condition when creating directory.
+            if (!is_dir($dir)) {
+                if ($exceptiononerror) {
+                    throw new invalid_dataroot_permissions($dir.' can not be created, check permissions.');
+                } else {
+                    debugging('Can not create directory: '.$dir, DEBUG_DEVELOPER);
+                    return false;
+                }
             }
         }
     }